Buttonhole-sewing machine.



G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION FILED 1113.10, 1912 14 SHEETS-SIIBET 2.

9 zsg M0 12 a0 N m I/y/illwsses Z In veizorsff 4. M4 Z G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION FILED 11.13.10, 1912.

1,063,880. Patented June 3, 1913.

14 SHEETS-SHEET 3- COLUMBIA vumumuvn cunwmmmurou. n, c.

G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION FILED FEB. 10, 1912.

1,063,880, Patented June 3, 1913.

14 SHEETS-SHEET 4.

X AMZ imzy wz W 3 G. S. HILL. BUTTONHOLE SEWING MACHINE.

APPLICATION mum FEB. 10, 1912.

1,063,880, Patented June 3, 1913.

14 SHEETS-SHEET 5 Maw-$565.- M X W. 777 a/ZM $445 COLUMUIA PLANOGRAI'HIO-,WASHINOTON. 0. C4

[have/Mov s G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION IILIID FEB.10.1912.

Patented June 3, 1913.

14 SHEETSSHEET 6.

COLUMBIA rmNoulzAvu 60.. wAsmNn'm D. c.

SHEET 7.

14 SHEETS- Patented June 3 G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION FILED FEB. 10, 1912.

Dave-1120163.- W

G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION FILED FEB. 10, 1912. 1,063 880. Patented June 3, 1913.

14 BHEETS-SHEET B.

winesswgsfnvgntons sou/mum MOGIIAPII 0.. WASHINGTON. 04 C G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION FILED FEB. 10 1912.

Patented June 3, 1913.

14 BHEETS-SHEET 9.

fizueni'ors':

G. S. HILL.

BUTTONHOLB SEWING MACHINE.

AYPLIOAIION FILED FEB. 10, 1912.

1 ,O63,880, Patented June 3, 1913.

14 SHEETS-SHEET 10.

fiauermlonsn- 7 1 M ZQJWMM ywm G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION IILED IBB. 10, 1012.

1,063,880. Patented June 3, 1913.

14 BHEBTSBHBET 11.

COLUMBIA l L/mousuPH cm. WASHINGTON. 04 c.

G. S. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION FILED I'BB.1U,1912. 1,063,880, Patented June 3, 1913.

14 SHEETS-SHEET l2.

frwenoms;

my ZWUWZZ COLUMBIA PLANOURAPH cu.,wA.-mlNn1nN. n. c

G. s. HILL.

BUTTONHOLE SEWING MACHINE.

APPLICATION FILED FEB.10,1912

1,063,880. Patented June 3, 1913.

14 SHEETS-BHEET14.

hihwsses:

t JNITED STATES PATENT OFFIOE.

GEORGE S. HILL, STRAFFORD, NEW HAMPSHIRE, ASSIGNOR T0 UNITED SHOEMACHINERY COMPANY, OF PATERSON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

BUTTONI-IOLIJ'SEWING MACHINE.

LOtiIifiBO.

Specification of Letters Patent.

a t en tctl June 3, 191 3.

To all ii /mm it may concern Be it known that l, Gnonon S. then, acitizen of the United States. residing at r trallord. in the county ofStrall'ord and ritate ol New Hampshire, have invented certain new and.useful improvements in liuttonhole-Sewing ltlachines; and 1 do herebydeclare the :t'ollowing to he a full, clear, and exact lescription oithe invention, such as will enable others skilled in the art to which itappertaii'is to make and use the same.

The invention relates to buttonhole sewing machines of that class inwhich a work holding clamp and a stitch lorming mechanism are relativelymovable to term overedge stitches extending along the sides and aboutthe ends oi. the lnittonholc.

The object of the invention is to produce a huttonhole sewing machine ofthis type having its various parts and mechanisms constructed andarranged in an improved and simplilied manner, and having an improvedmode of operation whereby the machine is adapted to cut and sew abuttonhole at a greater rate of speed and in a more uniformly reliableand satisfactory manner than the hutt'onholc sewing machines heretol'orein use.

With these objects in view the invention comprises the features ofctmstruction and combination of parts hereinafter described and settorth in the claims.

The various features of the invention will he ll1'l(lt.t'Sl()O(l lrom aninspection of the accompanying drawings and the jlollowing detaileddescription of the machine illustrated therein.

in the drawings. Figure 1 is a trout elevation of a buttonhole sewingmachine embodying the features ot the invention in their preferredforms; Fig. 2 is a right side elevation partly in section; Fig. 3 is aplan view partly in section; Fig. -t is a vertical sectional view online i t. Fig. 3; Fig. 5 is a central longitudinal sectional viewlooking from the right side of the machine; Fig. (3 is a sectional planview. the section being taken below the head of the machine; Fig. T is ahorizontal sectional view on line 7-T, big. 1; Fig. 8 is a detailsectional view on line 8*3, Fig. 1; Fig. 9 is a similar view showing theparts in a ditlerent position. Fig. 10 is a detail side elevation partlyin section showing the work holding clamp and cutter with the cutter incutting posh lion; Fig. ll is a detail plan view of the turret carryingthe under needle and cooperating looper, showing the looper in posilionto present the loop taken from the upper needle over the point ol theunder needle; Fig. 19 is a detail vertical sectional view showing theparts which operate upon the work; Fig. I? is a longitudinal section atthe turret carrying the under needle and looper showing the Formationot. the under loop by the needle; Fig. it is a plan view of the turretwith the parts in a similar po sition; Fig. is a front elevation partlyin section ol the turret; and devices carried thereby; Fig. ltl is adetail plan view partly in section showing the work clan'iping devices;Fig. ii is a sectional elevation on line li- T, Fig. ll); Fig. 18 is adetail plan view ot the gear which towns the carrier for various ol' theoperating and controlling cams; Fig. It) is a sectional elevation online lit--19 Fig. 18; Fig. 20 is a sectional elevation showing thestarting mechanism tripped to start the machine; Fig. 9.1. is a similarview with the parts in a dillerent position; Fig. 22 is a sectionalelevation showing the upper thread tension; and Fig. 23 is a dia' gramshowing the arrangement of the stitches about the buttonhole."

The machine illustrated comprises gen erally a work clamp 'lor holdingthe material to be operated upon, a cutter for cutting av buttonhole inthe material. stitch forming mechanism comprising a straighteve-pointedupper needle. a curved-eyepointed under needle, and a cooperatinglooper, and mechanisms for operating the clamp, cutter, and stitch:t'orming mechanism and for relatively moving them to properly positionthe material for cutting and then sewing the buttonhole. and forrelatively feeding and turning the clamp and stitch torming mechanismduring the operation of the stitch forming mechanism to form over-edgestitches extending along the sides and about the ends ot the butt mhole.The relative movements referred to are secured in the machineillustrated by movement of the work clamp and by turning the stitchforming mechanism, although it will be nnderstood that the mechanismstor etl'ecting these relative movements are is well adapted for movingthe cutter and stitch forming mechanism, or turning the clamp, and maybe embodied in machines in which the relative movements are thussecured.

The operative parts of the machine shown in the drawings are carried bya frame 1 supported on a base 2 to which the frame is connected bytrunnions 3 so that it may be swung up to give access to the parts onits under side which. are normally inclosed and protected by the base.

The work clamping devices comprise work supporting plates 4: arranged topass on opposite sides of the stitch forming mechanism and connected tothe clamp carriage 5 by the pivot screws (3 4t, 5, 6, 16 and 17). Thework is clamped on the plates it by clamping jaws 7 pivoted on the endsof the clamp carrying arms 8. The clamp arms are pivotally supported inblocks 9 which are provided with ribs engaging grooves 10 in the plates4., and are held in adjusted position on the plates by the clampingscrews 11 which pass through slots in the blocks. The work supportingplates 4 are forced normally toward each other by the springpressed bars12 which are mounted in supports 13 rising from the clamp carrier 5, andare provided with depending ends engaging grooves 14 in the plates. Thebars 12 are IOlCCCl forward by springs 15, and the forward position ofthe bars and connected work supporting plates is determined byadjustable stop screws 1.6 carried by collars 17 secured. to the outerends of the bars. The stop screws are provided with reduced endsengaging holes in the caps for the bar bearings, and with shoulders forengaging the caps and determining the inner position of the worksupporting plates. Vhen the machine is at rest the parts are in theposition indicated in 16 and 17, with the plates 4t in their innerposition and the clamps 7 open to receive the material and to positionit in proper relation to the buttonhole cutting devices. After thematerial is placed between the clamps and the work supporting plates 4,and the machine is started, the cutting devices are operated to cut thebuttonhole. The movement of the cutter is also utilized to close thework holding clamps. thus simplifying the clamp operating devices andreducing the number of operating cams. After the buttonhole is cut andthe work clamped. the clamp carriage is moved forward to bring thebuttonhole into proper relation to the stitch forming mechanism, andduring this forward movement the plates 4 are swung away from each otherto spread the buttonhole. The devices for thus moving the platescomprise the cam projections 18 formed on a block 19 and arranged to beengaged by the projections 20 on the plates. The block 19 is mountedupon a bracket- 21 which is secured to the under side of the frame 1,and also forms a support for the under needle turret and for the clampcarriage 5.

The devices for cutting the buttonhole comprise a lower cutter block 22which is supported upon the front end of a tongue 23 projecting for ardfrom the block 19, and a cutter blade or die 24 secured in the end of anarm which projects forward from a yoke 26. The ends of the yoke arepivotally supported on trunnions 27 carried by lugs 28 rising from theframe 1 (Figs. 1 and 6). A lever 29 is pivoted to the rear side of theyoke, and one end of this lever is arranged to engage a cam 30 formed onthe upper surface of the cam carrying gear 31. other end of the leverbears against a set screw 32 on the yoke, which may be adjusted to bringthe cutter into proper operative relation with the under cutter blockwhen the end of the lever 29 rides on to the high part of the cam 30(Fig. 10). The tongue 23 and cutter block 22 are firmly supported duringthe action of the cutter by a plate 23 which is secured to the top ofthe under needle turret.

The devices for operating the work holding clamp comprise arms 33carried by a rock shaft 34 and engaging slots 35 in the clamp arms 8(Figs. 1., (3, 1,0 and 12). The rock shaft 34 is mounted in bearingsformed in the supports 13 on the clamp carriage, and is forced in adirection to open the clamp by a torsional spring 36, one end of whichis engaged with one of the supports 13, and the other end of whichengages an arm 37 extending vertically from the rock shaft. The upperend of the arm 37 carries an adjustable screw 38 the end of whichengages a bearing block 39 on the cutter yoke 26 when the work clamp isin position to receive the work. .Vhen the cutter is operated, themovement of the yoke 26 moves the arm 87 forward, thus rocking the rockshaft 84 in a direction to close the work clamp. After the work clamphas been thus closed itis held closed until the sewing of the buttonholeis completed and the clamp moved into position for the removal of thework preparatory to the next cycle of operations. The devices forholding the clamp closed comprise a spring-prcssed latching pin 40mounted in a vertical projection on the hub of one of the arms 33 andarranged to engage a shoulder all on one of the supports 13 (Fig. 1.2).The shoulder 1-1 is formed at the lower end of a bearing 42 in which aspring-pressed latch operating pin 43 is mounted to move vertically. Thelatch oper ating pin is provided at its upper end with a V-shaped head44 arranged to cooperate with a stationary cam 45. The cam 45 is pivotedin a bracket secured to the head of the machine, and is provided with atail piece 46 which prevents movement of the The rain toward the rightin Fig. 12. The cam is held .in normal position by a spring l7 whichwill yield to allow the ram to move toward the let't. When the elaniipis elosed hy the movement of the cutter in eutting the material, thelateh *tO snaps up in trout ot the shoulder l1. and holds the olalnp inclosed position. During the 't'orward movement ot' the clamp airriagethe head ot. the lateh operating pin rides under the "am 45, and theearn yields to allow the head to pass freely by it. Al'ter the head ofthe pin has passed the eam returns to its normal position. A t't'er thehuttonhole has been sewed the elamp is returned to its initial position,and during this movement the ram to arts to press the lateh operatingpin downward. thus disengaging the lateh pin trom the shoulder t1. andallowing the spring so to open the elamp jaws. The opening movement otthe elamp is limited lrv the engagement of the hearing for the pin it)with a stop lug 48.

The elanip 'arriage is in the form ot a skeleton traine, as shown inFig. 7, whieh is provided with hearing surtaees ll) aranged to movetreely lietween hearing sur- 't'aees formed on the under side ol the'lrauie t and on the upper side ol the turret ln'aeket 21. The carriageis also provided with hearing surt'aees 5t. whieh move l'reel) betweensurtaees on the under side ol the frame I and on supporting plates 52seeured to the frame (Figs. 10 and IL). The earriage is movedlongitudinally or lengthwise ot' the huttonhole to shift the work 'tromeutting to sewing position, to teed the work during the sewing, and toreturn the work to initial position alter the huttonhole is rouipleted,hy a ram groove 5 1 formed in the under side of the ram earnvii'ig gearll, whieh engages a roll. earried on the upper end ot a stud 5t seeuredin the earriage. 'lhe stud passes through a pivot liloek 55 arrai'igedto slide in a slot 5t; termed in the frame '1. and torms a pivot aboutwhieh tho earriage is swung to move tho work elamp amt work laterally insewing along the sides of the eve of a. liutt'onhole. 'lhe deviees 't'orswinging the elamp earriage laterally eomprise a lever 57 mounted uponthe Frame 1 and having one end pivotallv eonnerted to a hloek 3S whiehengages a slot it) in the rear end ot' the earriage. and the other endprovided with a roll engaging a eam groove formed in the upper taee ol agear tit).

The stiteh :torming deviees eomprise a straighte ve pointed upper needletil whieh is arranged to pass through the 'tahrie at a. eertain distaneefrom the edge ol' the huttonhole. a eurved-e ve pointed under needle ofarranged to pass through the huttonholo slit, and a looper (33 fortaking a loop of thread from the upper needle and passing it, over theend of the under needle when it is in its retraeted position, so thatthe under needle will pass up through the loop when it is advaneed. Theneedles are arranged to pass through a throat plate itwhieh is arrangedover the under needle as is usual in this type ot' huttonhole sewinglnaehiner. During the sewing operation the under needle is advaueedthrough the loop of upper needle thread held In the looper. and after ithas reaehed its upper or advaneed posilien it is slightly retraeted ordipped to term a loop through whieh the upper needle passes in itsdeseeuh and then the under needle is returned to its retraeted position.During the sewing ot a huttonhole the stiteh torming deviees are rotatedor turned through a eoinplete revolution. so that overseam stilt-hes aretermed along the sides, ahout the eve. and aer ss the end of thehuttouhole. In order that the stiteh 'lorming meehauism may he thusrotated, the upper needle is tt't'tlltlltitll seeured in a bar mountedto reeiproeate through a rotary head or sleevet and the under needle andloope' are mounted in a rotary turret.

The upper needle (31 is seenred at the lower end ol a hollow needle har(i5 whieh is mounted to ltt'ltlltit'tltt! through a sleeve, on and anupper hau'ing ($7. The needle liar is eonneeted with the sleeve hy a keyand slot so that the l):ll' will rotate with the sleeve while heing treeto reeiproaite vertieallv through it. The sleeve is mounted to turn in ahearing tie. amt a sproeket wheel (it) is seeured to the sleeve and isrotated through a eolnplete revolution during the sewing ol' eaehhuttonhole h v a ehain passing ahout the sproeltet wheel. over thetightening sproeket T1 and tllltltlt a sproeket wheel 72 seeured to theupper end ot a verti eal shalt T3. The needle liar is rta-iproeattatthrough a erauk T-l seeured to the front end of a e 'ank shat't T5 amteonneeled with the needle har lrv link To. the upper end ot whieh ispivoted to a sleeve 77 surrounding the needle liar. The erank shat't T7)is driven t'rom a driving shat't 7s whieh is arranged out ol axialalinement with the erank shatt aml is eonneeted therewith h vdill'erential erank meehanism adapted to impart a slow movement to theneedle liar during the first; part ot its downward movement. and a rapidmovement to the bar during the lower part. ol its reeiprta-ation. Thiserank lneehanism eomprises a erank pin 79 on the inner end ot the erankshatt T5 whieh engages a. radially extending slot fit) 'lormed in an armSt whieh is seeured to the forward end ot the driving sha'l't TH. 'lhesha'l't T8 earries The needle vances the under needle from its retractedto its advanced position and then slightly retracts or dips the needleto form a loop through which the upper needle may pass, as indicated inl igs. 5, 19 and 18. The slot 03 in the needle carrying arm ispreferably curved as shown, since this reduces the throw of the arm 89requisite for imparting the reciprecation and dip to the needle. Theactuator arm S0 is oscillated during the forn'iation of each stitchthrough an arm 9% projecting from the sleeve 90 and connected by meansof a link 95 with one end. of a lever 96. The lever 00 is pivoted upon afixed bracket 97 which is secured to the frame of the machine, and therear end of the lever is connected by a link 98 with a crank 99 on theend of the driving shaft 8-1- (Figs. 1, 5 and 1.2). This constructionand arrangement of under needle carrier and driving connections enablesthe under needle to be reciproeated at a high rate of speed withoutstrain or undue wear upon the parts.

The crank for actuating the under needle nieclmnism, and thedifferential crank mechanism for reciprocating the upper needle, are soarranged that; both needles are withdrawn to their retracted position atsubstantially the same time, thus simultaneously tightening both theupper and under threads to set the stitches. This insures a uniforminterlocking of the stitches and location of the purl. The slow movementimparted to the upper needle during the first part of its downwardstroke, and the rapid completion of its reciprocation, enables theneedles to be thus simultaneously moved to retracted position. Thearrangement of the ditfcrential crank mechanism is such that during thehalf revolution of the driving shaft 84, which advances and dips theunder needle, the movement of the upper needle is not sufficient tobring its point below the loop formed by the upper needle, and duringthe completion of the rotation of the shaft 8% which retracts the underneedle the downward movement of the upper needle is eo1npleted, and theneedle returned to its upper or retracted position.

The eye of the upper needle extends through the needle substantiallyparallel to the line of feed, and the upper thread i is threaded throughthe needle in the direction of the feed so that the thread will drawfreely through the eye during the sewing. The thread leads to the eye ofthe needle through a tension device 102, through the guides 101 of theslack thread controlling device down through the needle bar, and througha light tension 100 on the lower end of the needle bar. As the needlebar rises it; acts to draw the upper thread taut to tighten and set thestitch, and during the descent of the needle bar it gives up slackthread between its eye and the work. A. part of this slack threadrequired to form that side of the loop carried down through the work bythe eye of the needle which extends from the previous stitch to the eyeof the needle. The descent of the needle, hmvever, gives up more slackthread than is required, and the surplus slack thread is taken up by theengagement of the thread with the upper bearing 67 through which theupper needle reciprocates. This bearing in the form of a sleeve, theupper end of which is so arranged that the upper end of the needle barpasses down within the sleeve during its descent, thus causing thethread to engage the upper end of the sleeve and be drawn back throughthe eye of the needle. The sleeve is mounted in the head of the machineso that it may be vertically adjusted, and is held in adjusted positionby a set screw 67. hen the loop of thread carried through the work bythe upper needle and held by the looper for the passage therethrough ofthe under needle is released by the looper, the slack thread in the loopis drawn up about the under needle by a vertically reciprocating threadfinger 101 which coiiperates with the thread guides 101. The threadfinger is arranged to pass up between the thread guides 101 and is soarranged that it is somewhat below the thread when the upper needle isin its retracted position. As shown, the thread finger is secured to thecrank 99 on the shaft 8 1 through which the under needle and looper areactuated. lVhen the upper nee dle is in its upper position the looperholds a loop of upper needle thread in position over the upper end ofthe under needle. As the shaft 84 turns through a half revolution theunder needle is advanced and the looper is retracted, and as the looperreleases the loop the thread finger engages the thread between theguides 101 and withdraws the slack thread from the loop and draws theloop up about the under needle. During this time the upper needle hasbeen moved slowly down through the first part of its stroke, and duringthe continued downward stroke of the upper needle the thread finger 101is retracted and gives up the slack thread which it has drawn.

The under thread t leads from the eye of the under needle through asecond eye or guide 103, through a guide eye 10% on the thrad arm theneethrough a tixed guide 105 earried on the turret. through a tension .1116on the turret. and theme through the hollow link 95. From the link 5)?)the thread l ads through deviees which are operated to prevent thetwisting ol? the under and stay thr ads one about the other by therotation of the turret, whieh deviees will be more 'tully describedherea'lter. As tho mulor needle is retrarted tho thread eyes in theneedle and on the needle -arrier cooperating with tho lix-od tin-adguide 105, draw up the slaek in the under thr ad and tighten and set thostitoh, without the aid or intervele tion of any additional takeup orthread tightening deviees. The stay thread or eord 1 ads through theguide in the throat plate, through a guide 107 in the threw-arm braeket10S whieh supports the throat plate and plate 13, through guide eyes.109 and 111), through tho hollow link 95, and thenoe to the guidingdeviees above ret'erred to which prevent twisting ot the under and staythrzads about *aeh other. After the upper needle has passed down throughthe loop o1 under needle thread Formed by dipping the under needle, andwhile tho under needle is being retrarted, the looper 3 engages thoupper needle thread between the eye 01. tho needle and tho work, andduring the movement of the needles to their retraeted positions rarriestho loop o1. thread thus taken over the end o1? tho under needle, sothat on tho next upward stroke of the under needle it will pass upthrough this loop of upper tin-ad. In tho eonstruetion shown, the looper'3 is so oper: ted that it passes the upper needle on the side oppositeto that on whieh the under needle passes, 2', (a, on the front side orside toward the direction oi the teed, and is provided with a heel 111whieh is arranged on the side of the looper away from the needle. Thelooper is provided with a laterally projeeting shank by which it isadjustably seenred in one end ot the looper arm 112. The loope arm ismounted upon a vertieal pivot '11?) carried by the end ot a horizontalarm 1i1-l-. The arm i111 seenred to the upper end ot a vertiezl rookshatt 115 whieh is mounted in the turret, and is provided at its lowerend with a 'adially projeeting arm 1113. The arm 116 is eonneeted by alink 11'? with an arm 111% depending 'l'rom the sleeve 90 whieh earriesthe needle aetuating arm St). 'hen the sleeve is roeked to re traet theunder noodle, the vert'ie: l shaft. 115 is turned to swing the arm 111-and looper earrying arm 119 in a direetion transversely o1 the direetionof the Feed to oarry the point ol? the looper past the trout side of theupper needle. As the looper '2tll' \'ll'1Q arm 11:. is thus moved bodilyin a horizontal plane it is also swung late 'ally in the direction ofthe feed about its vertical pivot 113, and as the looper arm eolnpletesits 'l'orward movement this lateral movement; brings the loop carried bythe looper over the end of the under noodle. This position ot the looperis indieated in Figs. 5 and 11.. The deviees t'or swinging the looperearrying arm laterally oomprises a ram slot 119 formed in a stationant'plate 11121) and engaged by a roll earried by the looper airying arm andarranged on the opposite side ot the pivot 11?) lrom the looper. Theconstruetion and arrangement of the looper supporting and aetuatingdeviees enables the loopor to be maintained under positive eontrol andto be aetuatod at a high rate o1 speed without strain or undue :lrictionand w \ar upon the operating parts.

The turret htw \\'ltl('l1 earries the under thread meehanism and throatplate is mounted in bearings tormed in the turret braeket 31 and isprovided at its lower end with a sproekel wheel 121 whieh is eonneetedwith a similar sproeket wheel 1122 on the lower end ol the sha'lt- 7?)by a ehain 193 whieh passes about the sprookot wheels and two anadjustable tightening sproeket 19-1. During the sewing ol eaehbnttonhole the shatt Til is turned through a eomplete revolution. andthrough the sproeket wheels and ehains deseribed, turns the stitoht'orming moehanism through a romplete revolution. In the eonstruetionshown, the rotation of the shal't T 3 and o1" the stitoh Formingmeehanism is always in the same direetion, these parts being turnedrotation at'ter rotation during the sewing ol sueeessive buttonholes.The devioes l'or thus rotating the shatit 7?) and stitoh lormingmeehanism eomprise driving eonneetions between the rotary gear (30 andthe sha'lt T23. and a ram operating on these eonneetions to vary themovement im parted to the shalt 721 and stitoh torming moehanism by therotation o1? the gait". As shown, the driving eonneetions eomprise anarm or link 125 one end o1 whieh is pivotally oonneetod to a pin 1213 onthe gear (it). and the other end ol' whieh is eonnerted by a link 1-37to an arm 12h soenred to the shal't Til (l igs. 1. h and 9). The link12.3 earrios a roll 12!) whieh travels in a eam groove tilt) formed in adisk 1:31 v\'ltlt'il is seoured in a braeket 1 3;. During the operationof the stitoh l'orming lttttllnlllr-tlll the gear tit) is dri\en througha single revolution by a pinion lit-l soeured to a vertieal shatt 131-.The upper end ol' the shal't lit 1- is eonneeted by a universal joint toa shal't seotion 135 the upper end ol' whieh earries a worm wheel 1 31'engaged by a worm on the driving shatt 8|. 'lhrongh these eonneetions auni term and eontinuous movement is imparted to the gear (it) during theoperation oi. the stitoh t'orming moolmnh-nn. 'lhe ram groove tilt) andthe arms and links (amneoting the gut and the shatv 7 are soproportioned and arranged, however, that the stitch forming mechanism isheld stationary or moved at varying speeds during the sewing about thebuttonhole, according to the part of the buttonhole at which the stitchforming mechanism is operating. In the machine shown, the parts are soproportioned and arranged that the first stitch in a buttonhole isformed at the end of the buttonhole slit, and the last stitch iscompleted in the same needle hole in which the first stitch was begun,as indicated in Fig. 23. The position of the parts when the sewingmechanism is started and stopped is indicated in Fig. 8. During thefirst advance stroke of the needles the cam roll 129 moves in the part138 of the cam groove 130, which is so shaped that no rotary movement isimparted to the stitch forming mechanism until after the needles havepassed through the work. After the first stitch is formed, the rolltravels in a part of the cam groove which accelerates the movementtransmitted to the stitch forming mechanism from the gear 60 so that thestitch forming mechanism is rotated at a comparatively rapid speed informing the stitches across the lower end of the buttonhole. Therotation of the stitch forming mechanism is then retarded in sewingalong the sides of the buttonhole, is ac celerated in sewing about theeye of the buttonhole, is again retarded in sewing along the oppositeside of the buttonhole, and is again accelerated in passing from theside to the end and sewing across the end of the buttonhole. In formingthe last stitch the needles pass through the material at the same pointthey passed in forming the first stitch, and thereafter the cam rolltravels in the part 138 of the cam groove so that no rotary movement isimparted to the stitch forming mechanism during the last retractingmovement of the needles, and the stitch forming mechanism is stopped inproper position for the sewing of the next buttonhole. By the mechanismdescribed the rotation of the stitch forming mechanism may be accuratelyand uniformly controlled while the actuating mechanism is operated at ahigh rate of speed.

As has been stated, the under thread t and stay thread 8 are led throughthe hollow link 95 forming a part of the driving connections for theunder thread mechanism. This link rotates with the turret carrying theunder thread mechanism, and the lower end of the link is provided with apin 139 which lies between the under and stay threads and provides twoguides for the threads at the lower end of the link. Since the turret isturned rotation after rotation in. the same direction, the stay andunder threads would be twisted one about the other below the lower endof the link 95 if means were not provided to avoid such twisting to--gether of the threads. In the construction shown, such twisting togetherof the threads is avoided or counteracted by providing guides for thethreads which are given a rotation for each rotation of the turret, andby providing a support for one or both of the thread supplies whichturns with these guides. As shown, one of the thread supplies 140,preferably that of the stay thread, is carried by a Support 141 securedto a vertical tube 142 which is mounted to turn in an eccentricadjustable bearing 143. The stay thread is'led from the thread supply140 down through the guiding tube 142 and thence through a guide eye 144to the guides at the lower end of the link 95. The under thread is ledfrom its supply through a guide tube 145 which directs the thread from apoint in line with the axis of the guide tube 142 down about the threadsupply 140 and into the guide tube 142 below the stay thread supply. Thethread leads from the lower end of this tube over a guide pin 146 whichdivides the lower end of the guide tube 142 into two guides similar tothe guides at the lower end of the hollow link 95. The guide tube 142 isgiven a rotation for each rotation of the turret, and in an oppositedirection, so that the twisting action of the turret is nullified andthe twisting together of the threads is avoided. The means for thusturning the guide tube 142 comprises a sprocket chain 147 passing over asprocket wheel 148 secured to the lower end of the tube, and over asprocket wheel 149 secured to the shaft 134 through which the stitchforming mechanism is rotated.

The mechanism for driving and stopping the shaft 84 which actuates thestitch forming mechanism and the mechanism for turning the stitchforming mechanism and under thread guides, comprises a continuouslyrotating driving pulley 150 which is loosely mounted on a sleeve 15].surrounding the shaft (Figs. 1, 2 and The pulley is provided with aninternal clutch face adapted to cooperate with a clutch disk 152 whichis keyed. on the shaft. The pulley carrying sleeve 151 is forced in adirection to engage the members of the clutch by a spring 153 interposedbetween the end of the sleeve and a disk 154 held on the end of theshaft by a collar 155. The pulley is moved against the tension of thespring to disengage the clutch members by pins 156 which pass throughthe hub of the clutch member 152, and are interposed between the end ofthe sleeve 151 and an actuator pinion 157. The actuator pinion is rockedin one direction or the other at proper intervals by a rack 158 securedto.

